The strange mystery of the shoelace and the horse

My teenage daughter mucks out our horse stalls during the week. Yesterday she just had to inform me that she found a strange item in ‘Moe’s” (short for Mozart) stall. She was picking up the poop when she saw what looked like a wide shoelace. She said she wondered how a shoelace got into his stall and looked at it more closely. She then said it looked like a snake skin, one that been shed. To get a better look at it she took it outside and washed it under the tap to find out that it was indeed a snake skin but with the now flattened snake still in it. Our assumption is that Moe saw the 18″ snake wiggle through his stall and promptly stomped it until flat.